---------
1. CPUFreq core and interfaces
2. CPUFreq notifiers
+3. CPUFreq Table Generation with Operating Performance Point (OPP)
1. General Information
=======================
cpu - number of the affected CPU
old - old frequency
new - new frequency
+
+3. CPUFreq Table Generation with Operating Performance Point (OPP)
+==================================================================
+For details about OPP, see Documentation/power/opp.txt
+
+dev_pm_opp_init_cpufreq_table - cpufreq framework typically is initialized with
+ cpufreq_frequency_table_cpuinfo which is provided with the list of
+ frequencies that are available for operation. This function provides
+ a ready to use conversion routine to translate the OPP layer's internal
+ information about the available frequencies into a format readily
+ providable to cpufreq.
+
+ WARNING: Do not use this function in interrupt context.
+
+ Example:
+ soc_pm_init()
+ {
+ /* Do things */
+ r = dev_pm_opp_init_cpufreq_table(dev, &freq_table);
+ if (!r)
+ cpufreq_frequency_table_cpuinfo(policy, freq_table);
+ /* Do other things */
+ }
+
+ NOTE: This function is available only if CONFIG_CPU_FREQ is enabled in
+ addition to CONFIG_PM_OPP.
+
+dev_pm_opp_free_cpufreq_table - Free up the table allocated by dev_pm_opp_init_cpufreq_table
3. OPP Search Functions
4. OPP Availability Control Functions
5. OPP Data Retrieval Functions
-6. Cpufreq Table Generation
-7. Data Structures
+6. Data Structures
1. Introduction
===============
OPP library facilitates this concept in it's implementation. The following
operational functions operate only on available opps:
opp_find_freq_{ceil, floor}, dev_pm_opp_get_voltage, dev_pm_opp_get_freq, dev_pm_opp_get_opp_count
-and dev_pm_opp_init_cpufreq_table
dev_pm_opp_find_freq_exact is meant to be used to find the opp pointer which can then
be used for dev_pm_opp_enable/disable functions to make an opp available as required.
opp_get_{voltage, freq, opp_count} fall into this category.
opp_{add,enable,disable} are updaters which use mutex and implement it's own
-RCU locking mechanisms. dev_pm_opp_init_cpufreq_table acts as an updater and uses
-mutex to implment RCU updater strategy. These functions should *NOT* be called
-under RCU locks and other contexts that prevent blocking functions in RCU or
-mutex operations from working.
+RCU locking mechanisms. These functions should *NOT* be called under RCU locks
+and other contexts that prevent blocking functions in RCU or mutex operations
+from working.
2. Initial OPP List Registration
================================
/* Do other things */
}
-6. Cpufreq Table Generation
-===========================
-dev_pm_opp_init_cpufreq_table - cpufreq framework typically is initialized with
- cpufreq_frequency_table_cpuinfo which is provided with the list of
- frequencies that are available for operation. This function provides
- a ready to use conversion routine to translate the OPP layer's internal
- information about the available frequencies into a format readily
- providable to cpufreq.
-
- WARNING: Do not use this function in interrupt context.
-
- Example:
- soc_pm_init()
- {
- /* Do things */
- r = dev_pm_opp_init_cpufreq_table(dev, &freq_table);
- if (!r)
- cpufreq_frequency_table_cpuinfo(policy, freq_table);
- /* Do other things */
- }
-
- NOTE: This function is available only if CONFIG_CPU_FREQ is enabled in
- addition to CONFIG_PM as power management feature is required to
- dynamically scale voltage and frequency in a system.
-
-dev_pm_opp_free_cpufreq_table - Free up the table allocated by dev_pm_opp_init_cpufreq_table
-
-7. Data Structures
+6. Data Structures
==================
Typically an SoC contains multiple voltage domains which are variable. Each
domain is represented by a device pointer. The relationship to OPP can be
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/slab.h>
-#include <linux/cpufreq.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/rculist.h>
}
EXPORT_SYMBOL_GPL(dev_pm_opp_disable);
-#ifdef CONFIG_CPU_FREQ
-/**
- * dev_pm_opp_init_cpufreq_table() - create a cpufreq table for a device
- * @dev: device for which we do this operation
- * @table: Cpufreq table returned back to caller
- *
- * Generate a cpufreq table for a provided device- this assumes that the
- * opp list is already initialized and ready for usage.
- *
- * This function allocates required memory for the cpufreq table. It is
- * expected that the caller does the required maintenance such as freeing
- * the table as required.
- *
- * Returns -EINVAL for bad pointers, -ENODEV if the device is not found, -ENOMEM
- * if no memory available for the operation (table is not populated), returns 0
- * if successful and table is populated.
- *
- * WARNING: It is important for the callers to ensure refreshing their copy of
- * the table if any of the mentioned functions have been invoked in the interim.
- *
- * Locking: The internal device_opp and opp structures are RCU protected.
- * Since we just use the regular accessor functions to access the internal data
- * structures, we use RCU read lock inside this function. As a result, users of
- * this function DONOT need to use explicit locks for invoking.
- */
-int dev_pm_opp_init_cpufreq_table(struct device *dev,
- struct cpufreq_frequency_table **table)
-{
- struct dev_pm_opp *opp;
- struct cpufreq_frequency_table *freq_table = NULL;
- int i, max_opps, ret = 0;
- unsigned long rate;
-
- rcu_read_lock();
-
- max_opps = dev_pm_opp_get_opp_count(dev);
- if (max_opps <= 0) {
- ret = max_opps ? max_opps : -ENODATA;
- goto out;
- }
-
- freq_table = kzalloc(sizeof(*freq_table) * (max_opps + 1), GFP_KERNEL);
- if (!freq_table) {
- ret = -ENOMEM;
- goto out;
- }
-
- for (i = 0, rate = 0; i < max_opps; i++, rate++) {
- /* find next rate */
- opp = dev_pm_opp_find_freq_ceil(dev, &rate);
- if (IS_ERR(opp)) {
- ret = PTR_ERR(opp);
- goto out;
- }
- freq_table[i].driver_data = i;
- freq_table[i].frequency = rate / 1000;
- }
-
- freq_table[i].driver_data = i;
- freq_table[i].frequency = CPUFREQ_TABLE_END;
-
- *table = &freq_table[0];
-
-out:
- rcu_read_unlock();
- if (ret)
- kfree(freq_table);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(dev_pm_opp_init_cpufreq_table);
-
-/**
- * dev_pm_opp_free_cpufreq_table() - free the cpufreq table
- * @dev: device for which we do this operation
- * @table: table to free
- *
- * Free up the table allocated by dev_pm_opp_init_cpufreq_table
- */
-void dev_pm_opp_free_cpufreq_table(struct device *dev,
- struct cpufreq_frequency_table **table)
-{
- if (!table)
- return;
-
- kfree(*table);
- *table = NULL;
-}
-EXPORT_SYMBOL_GPL(dev_pm_opp_free_cpufreq_table);
-#endif /* CONFIG_CPU_FREQ */
-
/**
* dev_pm_opp_get_notifier() - find notifier_head of the device with opp
* @dev: device pointer used to lookup device OPPs.
# CPUfreq core
obj-$(CONFIG_CPU_FREQ) += cpufreq.o freq_table.o
+obj-$(CONFIG_PM_OPP) += cpufreq_opp.o
+
# CPUfreq stats
obj-$(CONFIG_CPU_FREQ_STAT) += cpufreq_stats.o
--- /dev/null
+/*
+ * Generic OPP helper interface for CPUFreq drivers
+ *
+ * Copyright (C) 2009-2014 Texas Instruments Incorporated.
+ * Nishanth Menon
+ * Romit Dasgupta
+ * Kevin Hilman
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/cpufreq.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/pm_opp.h>
+#include <linux/rcupdate.h>
+#include <linux/slab.h>
+
+/**
+ * dev_pm_opp_init_cpufreq_table() - create a cpufreq table for a device
+ * @dev: device for which we do this operation
+ * @table: Cpufreq table returned back to caller
+ *
+ * Generate a cpufreq table for a provided device- this assumes that the
+ * opp list is already initialized and ready for usage.
+ *
+ * This function allocates required memory for the cpufreq table. It is
+ * expected that the caller does the required maintenance such as freeing
+ * the table as required.
+ *
+ * Returns -EINVAL for bad pointers, -ENODEV if the device is not found, -ENOMEM
+ * if no memory available for the operation (table is not populated), returns 0
+ * if successful and table is populated.
+ *
+ * WARNING: It is important for the callers to ensure refreshing their copy of
+ * the table if any of the mentioned functions have been invoked in the interim.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Since we just use the regular accessor functions to access the internal data
+ * structures, we use RCU read lock inside this function. As a result, users of
+ * this function DONOT need to use explicit locks for invoking.
+ */
+int dev_pm_opp_init_cpufreq_table(struct device *dev,
+ struct cpufreq_frequency_table **table)
+{
+ struct dev_pm_opp *opp;
+ struct cpufreq_frequency_table *freq_table = NULL;
+ int i, max_opps, ret = 0;
+ unsigned long rate;
+
+ rcu_read_lock();
+
+ max_opps = dev_pm_opp_get_opp_count(dev);
+ if (max_opps <= 0) {
+ ret = max_opps ? max_opps : -ENODATA;
+ goto out;
+ }
+
+ freq_table = kzalloc(sizeof(*freq_table) * (max_opps + 1), GFP_KERNEL);
+ if (!freq_table) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ for (i = 0, rate = 0; i < max_opps; i++, rate++) {
+ /* find next rate */
+ opp = dev_pm_opp_find_freq_ceil(dev, &rate);
+ if (IS_ERR(opp)) {
+ ret = PTR_ERR(opp);
+ goto out;
+ }
+ freq_table[i].driver_data = i;
+ freq_table[i].frequency = rate / 1000;
+ }
+
+ freq_table[i].driver_data = i;
+ freq_table[i].frequency = CPUFREQ_TABLE_END;
+
+ *table = &freq_table[0];
+
+out:
+ rcu_read_unlock();
+ if (ret)
+ kfree(freq_table);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_init_cpufreq_table);
+
+/**
+ * dev_pm_opp_free_cpufreq_table() - free the cpufreq table
+ * @dev: device for which we do this operation
+ * @table: table to free
+ *
+ * Free up the table allocated by dev_pm_opp_init_cpufreq_table
+ */
+void dev_pm_opp_free_cpufreq_table(struct device *dev,
+ struct cpufreq_frequency_table **table)
+{
+ if (!table)
+ return;
+
+ kfree(*table);
+ *table = NULL;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_free_cpufreq_table);
* order */
};
+#if defined(CONFIG_CPU_FREQ) && defined(CONFIG_PM_OPP)
+int dev_pm_opp_init_cpufreq_table(struct device *dev,
+ struct cpufreq_frequency_table **table);
+void dev_pm_opp_free_cpufreq_table(struct device *dev,
+ struct cpufreq_frequency_table **table);
+#else
+static inline int dev_pm_opp_init_cpufreq_table(struct device *dev,
+ struct cpufreq_frequency_table
+ **table)
+{
+ return -EINVAL;
+}
+
+static inline void dev_pm_opp_free_cpufreq_table(struct device *dev,
+ struct cpufreq_frequency_table
+ **table)
+{
+}
+#endif
+
+
bool cpufreq_next_valid(struct cpufreq_frequency_table **pos);
/*
#define __LINUX_OPP_H__
#include <linux/err.h>
-#include <linux/cpufreq.h>
#include <linux/notifier.h>
struct dev_pm_opp;
}
#endif
-#if defined(CONFIG_CPU_FREQ) && defined(CONFIG_PM_OPP)
-int dev_pm_opp_init_cpufreq_table(struct device *dev,
- struct cpufreq_frequency_table **table);
-void dev_pm_opp_free_cpufreq_table(struct device *dev,
- struct cpufreq_frequency_table **table);
-#else
-static inline int dev_pm_opp_init_cpufreq_table(struct device *dev,
- struct cpufreq_frequency_table **table)
-{
- return -EINVAL;
-}
-
-static inline
-void dev_pm_opp_free_cpufreq_table(struct device *dev,
- struct cpufreq_frequency_table **table)
-{
-}
-#endif /* CONFIG_CPU_FREQ */
-
#endif /* __LINUX_OPP_H__ */
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